Fixture means to support plural workpieces in a coplanar relationship



United States Patent [72] Inventors Roger Alexander Buttery,

Ferring, England Thomas Turnbull, Headington, England 21 Appl. No. 720,739 [22] Filed April 11, 1968 Continuation of Ser. No. 459,369, filed May 27, 1965. [45] Patented Aug: 18, 1970 w i i i [73] Assignee Quickl'it & Quartz Limited Walton, Stone, England a Corp. of Great Britain [32] Priority June 10, 1964 [33] Great Britain [31 1 No. 24,166/64 [54] FIXTURE MEANS TO SUPPORT PLURAL WORKPIECES IN A CO-PLANAR RELATIONSHIP Primary Examiner- Morris Kaplan Attorney Imirie, Smiley, Snyder and Butrum ABSTRACT: Apparatus for clamping chromatography plates by their end marginal portions during coating compris- 4 Cl i 4 D i Fi ing a vertically disposed pair of locating members and a com- 52 U 8 Cl 118 503 plementary pair of resilient supporting members actuated by l I I ancillary means effecting a progressive relative Clamping 51 l t Cl 6 A 14 movement comprising a series of cams coaxially mounted in l l n C spaced relation lengthwise of the apparatus Simultaneously operable to engage abutments carried transversely of the ap- [56] References C'ted paratus and connected to the clamping means whereby the UNITED STATES PATENTS ends of the chromatography plates are progressively clamped 1,3 84,328 7/1921 Middeldorf 269/153 X between the locating members and the resilient supports.

FIXTURE MEANS TO SUPPORT PLURAL WORKPIECES IN A CO-PLANAR RELATIONSHIP This application is a continuation of Serial No. 459,369, filed May 27, 1965, and now abandoned.

This invention relates to apparatus for maintaining a plurality of chromatography plates in co-planar relationship, for example, in coating chromatography plates for use in performing thin layer chromatography.

It is well known that in performing thin layer chromatography, chromatography plates made from glass, metal or synthetic plastics for example, having one planar surface coated with a thin layer of a suitable adsorbent material are used for the preparation of chromatograms as is more fully described for example in Thin-Film Chromatography by E.V. Truter (Clever-Hume 1963).

ln order to obtain reproducible chromatograms from test materials under the same experimental conditions, it is necessary that each chromatography plate used for preparing the chromatograms be coated with an identical uniform thin layer of absorbent material.

In an attempt to obtain a plurality of chromatography plates each coated with a uniform thin layer of adsorbent material, it has previously been proposed to apply the thin layer of adsorbent material to a plurality of juxtaposed supported chromatography plates, for example glass plates, by an applicator comprising a doctor blade which is arranged to spread a thin layer of the desired thickness over the upper planar surfaces of the glass plates as the applicator is moved thereover.

However, the difficulty in carrying out this method has been the difficulty in maintaining the upper surfaces of the juxtaposed glass plates co-planar, because slight variations in the position of the upper surface of the glass plates will result in the layers of adsorbent material applied being non-uniform.

The obvious way of overcoming this difficulty, namely the use of glass plates which have exactly similar thicknesses and which are rested on a perfectly uniform supporting surface is not economic because such exactly similar glass plates are very expensive.

Accordingly it is an object of the present invention to provide apparatus for maintaining a plurality of juxtaposed chromatography plates in co-planar relationship so that an identical uniform layer of adsorbent material may be coated thereon by an applicator moved over said plates despite variations in the dimensions, including the thickness, of the individual chromatography plates.

According to the present invention there is provided apparatus for maintaining a plurality of juxtaposed chromatography plates in co-planar relationship, for example for use in coating chromatography plates formed from glass, metal, or synthetic plastics, for thin layer chromatography, the apparatus comprising movable guide members for engaging marginal portions of the upper planar surface of each ofa plurality of chromatography plates, opposed resilient means for supporting said chromatography plates, and ancillary means for causing said guide members to sandwich said plates under pressure at said marginal portions to maintain the upper planar surfaces in co-planar relationship.

Preferably the resilient means comprises two parallel strips of resilient section, for example foam rubber or polyurethane foam arranged in spaced relationship each on a continuous supporting member.

Advantageously the movable guide members comprise two parallel inverted U-shaped members, one arm of the U being shorter than the other, the shorter arms being arranged to engage opposite marginal portions of the chromatography plates and the longer arms being connected to said ancillary means.

According to one embodiment of the invention the ancillary means comprises a rotatable spindle carrying one or more cams for bearing on transverse members, held in register with said cams, for supporting the guide members so that rotation of the spindle from a datum position will cause the guide members to engage said upper surfaces.

Desirably the longer arms of the guide members are pivoted about opposite ends of said transverse members so that in the datum position the guide members may be disengaged from said upper planar surfaces.

The invention also comprehends apparatus for use in coat ing chromatography plates comprising movable guide members for engaging marginal portions of the upper planar surface of each of a plurality of chromatography plates, and opposed resilient means for supporting said chromatography plates, said guide members being adapted for connection to ancillary means for causing said guide members to sandwich said chromatography plates under pressure at said marginal portions to maintain said upper surfaces in co-planar relationship.

ln order that the invention may be more clearly understood some preferred embodiments in accordance therewith will now be described by way of example with reference to the accompanying drawings in which like reference numerals designate the same or similar parts, and in which:-

FIGURE 1 is a plan view from underneath of one apparatus in accordance with the invention,

FIGURE 2 is an elevation partly in section of the left hand end of the apparatus of FIGURE l,

FIGURE 3 is a section on the line llI-Ill of FIGURE 1, and

FIGURE 4 is a view similar to that of FIGURE 3 but wherein the guide members are shown disengaged from the glass chromatography plates to facilitate removal of the glass plates.

Referring to the drawings, there is shown apparatus for maintaining a plurality of chromatography plates formed from glass, metal or synthetic plastics for example, in co-planar relationship and in the embodiment to be described the apparatus is for use in coating glass plates with a thin layer of adsorbent material, e.g. alumina, silica gel or *Sephadex" resin, the coated glass plates being used in thin layer chromatography. The glass plates are substantially all of the same width but not necessarily of the same length. I

The apparatus comprises two parallel aluminium T-shaped members 1 supported and spaced apart, according to the width of the glass sheets, by three transverse mild steel supports 2 chamfered at 3 and by an end transverse member 4. The two T-shaped members 1 support resilient means which in this embodiment comprises two parallel strips of polyurethane foam 5, although other resilient section may be used, for example foam rubber, each supported on one T-shaped member 1 and spaced apart as shown for supporting a plurality of glass chromatography plates 6 at their marginal portions 7.

The apparatus further comprises two movable guide members 8 arranged parallel to each other for engaging the marginal portions 7 of the upper planar surface of each of the plurality of chromatography plates 6. The guide members 8 comprise two parallel inverted U-shaped members, one arm 9 of the U being shorter than the other arm 10, the shorter arms 9 being arranged to engage opposite marginal portions 7 of the upper planar surface of the plates 6.

The longer arms 10 are connected to ancillary means for causing the guide members 8 to sandwich the plates 6 under pressure at their marginal portions 7 to maintain the upper planar surfaces of the plates 7 in co-planar relationship as will be hereinafter more fully described. The ancillary means comprises a spindle 11 rotatable by the handle 12 joined thereto, which spindle carries two cams 13 having integral flanges 14 secured by screws 15 to the spindle. The spindle may carry stops (not shown) to limit its rotational movement to half a revolution.

The spindle 11 passes through bushes 16 in the transverse members 2 and 4. The cams 13 bear on transverse members 17 which are free to move vertically in vertical slots 18 in the T-shaped members 1 but are prevented from horizontal displacement so that the transverse members 17 are held in register with the earns 13.

U The transverse members 17 support the guide members 8 by means of struts 19 bolted by bolts 20 to the longer arms 10 of I the guide members 8 and the struts 19 are pivoted at 21 to the transverse members 17 so that the longer arms of the guide members are pivoted about opposite ends of the transverse members 17. The transverse members 17 carry stops 22 which prevent sideways movement of the members 17.

In use a number of chromatography plates, for example glass plates 6 each having an upper planar surface are positioned side by side with their marginal portions 7 supported on the strips of polyurethane foam 5. In the datum position of the cams l3 (FIGURES 3 and 4) the transverse members 17 are free to move vertically so that the guide members 8 may be raised manually and the shorter arms 9 positioned for engaging the marginal portions 7 of the upper planar surface of each of the plurality of chromatography plates.

Rotation of the spindle by the handle 12 from the datum position of FIGURES 3 and 4 through half a revolution to the position shown in FIGURE 2 will cause the guide members 8 to be thrust downwardly in rubbing engagement with respective vertical sections of the T shaped members 1 which form plane abutments and engage the upper surface of each of the plates 6 so that the plates are sandwiched under pressure at the marginal portions 7 between the guide members 8 and the opposed resilient polyurethane strips 5. The shorter arms 9 contact the upper surface of each of the glass plates 6 and the natural resilience of the polyurethane foam maintains the marginal portions 7 in contact with the shorter arms 9 so that even if there are differences in the thickness of the glass plates or other eccentricities occur in the lower surface of the glass plates these differences are absorbed by the polyurethane foam which exerts a pressure over the whole of the marginal portions of the lower surface of the glass plates 6.

When the plates 6 are sandwiched as shown in FIGURE 2 a conventional applicator may be moved over the juxtaposed glass plates to coat the glass plates with a uniform thin layer of adsorbent material. The handle 12 is then rotated back so that the cams 13 are returned to the datum position of FIGURES 3 and 4 in which position the guide members 8 may be manually disengaged from the upper surface of the glass plates. This is done by merely swinging the guide members 8 outwardly from the glass plates as shown in FIGURE 4, since in the datum position the guide members lie in contact with the glass plates without sandwiching them. If desired the guide members 8 may be provided with handles to aid the manipulation thereof.

The glass plates coated with the thin layer of adsorbent material may then be removed from the apparatus and used in thin layer chromatography experiments and as each plate 6 bears an identical thin layer of adsorbent material the glass plates may be used for obtaining reproducible results from the same test material provided that other similar experimental conditions are used.

Instead of the use of the supports 2 for supporting the apparatus they may be retained solely as transverse ribs joining the two T-shaped members 1 and the apparatus may be supported by four vertical legs arranged in pairs and secured to the T-shaped members 1. For example a pair of legs may support each end ofthe apparatus.

Furthermore the T-shaped members 1 may carry guides in the form of vertical rods which are received in apertures in the transverse members 17 so that the guides prevent horizontal displacement ofthe members 17 and maintain them in register with the cams 13. The stops 22 are not then required. The aforementioned guides may also be employed to support the apparatus.

In an alternative embodiment ofthe invention the two guide members 8 are mounted on overhead transverse members which are pivoted at one side of the apparatus and may be locked in a horizontal position by locking means on the other side of the apparatus. In this embodiment of the invention the rotatable spindle ll, cams l3 and transverse members 17 are not required since the guide members 8 suspended from the overhead transverse members may be locked in a position where the guide members 8 sandwich the glass plates between the polyurethane foam strips 5 and the shorter arms 9.

In an even further embodiment of the invention two spindles mounted towards each end of the transverse supports 2 may be used to raise and lower the guide members 9 and by using a suitable arrangement of cams, the spindles may be arranged so that on rotation of one of the spindles both spindles lift the guide members 8 upwardly and outwardly from the glass plates in the datum position so that the guide members need not be disengaged manually from the glass plates 6.

The invention, therefore, comprehends any other ancillary means for example clamps, for causing the guide members to sandwich the chromatography plates under pressure at their marginal portions to maintain the upper planar surfaces of the chromatography plates in co-planar relationship and accordingly the present invention comprehends apparatus for use in coating chromatography plates comprising movable guide members for engaging marginal portions of the upper surface of each of a plurality of said chromatography plates and opposed resilient means for supporting said plates, the guide members being adapted for connection to the ancillary means.

By the use of the present invention there is provided apparatus which is simple to operate and which can be used for example in the application of a uniform thin layer of adsorbent material for chromatographic purposes to glass in sheet form of varying thicknesses and having only one substantially planar surface, for example, one surface which has been ground and polished.

I claim:

1. Apparatus for clamping a plurality of juxtaposed chromatography plates in co-planar abutting relationship for use in performing thin layer chromatography, including clamping means, for engaging both end marginal portions of the plates which comprise a vertically disposed pair of longitudinally extending movable locating members and a complementary pair of longitudinally extending resilient supporting members for the chromatography plates, the longitudinally extending sides of the apparatus including vertical sections which each form a plane abutment for a respective one of said locating members when lowered towards and raised from the resilient support, said vertical sections being spaced apart to snugly receive between them the chromatography plates resting on the resilient supports, and that the locating members are constituted as guide members for an applicator intended to slide between them in a coating operation, and ancillary means effecting a progressive relative movement between the pair of locating members and the pair of resilient supporting members to clamp the plates therebetween, comprising a series of similar cams coaxially mounted in equi-spaced relation lengthwise in the apparatus, and means for simultaneously actuating the cams, rigid abutment means for the cams mounted transversely of the ap paratus and connected to the clamping means, said abutment means coacting with said cams and being movably responsive thereto so that on the simultaneous actuation of the cams a progressive relative movement between the locating members and the resilient supporting members is obtained to clamp the chromatography plates in position for coating, wherein the respective locating members are constituted by a vertical inner wall of a respective inverted U"-shaped channel member, of which the parallel outer wall is hingedly connected to the said abutment means, the hinge being outwardly offset with respect to the said vertical inner wall, and the said vertical inner wall overlies the vertical section of the respective locating member when the locating member is in operative position.

2. Apparatus for clamping a plurality of juxtaposed chromatography plates in co-planar abutting relationship for use in performing thin layer chromatography, including clamping means, for engaging both end marginal portions of the plates which comprise a vertically disposed pair of longitudinally extending movable locating members and a complementary pair of longitudinally extending resilient supporting members for the chromatography plates, the longitudinally extending sides of the apparatus including vertical sections which each form a plane abutment for a respective one of said locating members when lowered towards and raised from the resilient support, said vertical sections being spaced apart to snugly receive between them the chromatography plates resting on the resilient supports, and that the locating members are constituted as guide members for an applicator intended to slide between them in a coating operation, and ancillary means effecting a progressive relative movement between the pair of locating members and the pair of resilient supporting members to clamp the plates therebetween, comprising a series of similar cams coaxially mounted in equi-spaced relation lengthwise in the apparatus, and means for simultaneously actuating the cams, rigid abutment means for the cams mounted transversely of the apparatus and connected to the clamping means, said abutment means coacting with said cams and being movably responsive thereto so that on the simultaneous actuation of the cams a progressive relative movement between the locating members and the resilient supporting members is obtained to clamp the chromatography plates in position for coating, wherein the longitudinally extending sides of the apparatus are in the form of T-shaped angle bars, the lower vertical limbs of each T"-shaped angle bar being slotted vertically at intervals opposite to the cams, said abutment means comprising a series of abutment members located in said slots respectively under the cams, said abutment members being individually hinged at each end to the respective locating members.

3. Apparatus for clamping a plurality of juxtaposed chromatography plates in co-planar abutting relationship for use in performing thin layer chromatography, including clamping means, for engaging both end marginal portions of the plates which comprise a vertically disposed pair of longitudinally extending movable locating members and a complementary pair of longitudinally extending resilient supporting members for the chromatography plates, the longitudinally extending sides of the apparatus including vertical sections which each form a plane abutment for a respective one of said locating members when lowered towards and raised from the resilient support, said vertical sections being spaced apart to snugly receive between them the chromatography plates resting on the resilient supports, and that the locating members are constituted as guide members for an applicator intended to slide between them in a coating operation, and ancillary means effecting a progressive relative movememt between the pair of locating members and the pair of resilient supporting members to clamp the plates therebetween, comprising a series of similar cams coaxially mounted in equi-spaced relation lengthwise in the apparatus, and means for simultaneously actuating the cams, rigid abutment means for the cams mounted transversely of the apparatus and connected to the clamping means, said abutment means coacting with said cams and being movably responsive thereto so that on the simultaneous actuation of the cams a progressive relative movement between the locating members and the resilient supporting members is obtained to clamp the chromatography plates in position for coating, comprising at least one locating member which is hingedly connected to the abutment means to be swung away from the respective resilient supporting member after the clamping effect has been changed sufficiently by resetting the cams to release the chromatography plates, and expose the corresponding ends of the plates to facilitate removal of the plates from the respective side of the apparatus.

4. Apparatus for clamping a plurality of juxtaposed chromatography plates in co-planar abutting relationship for use in performing thin layer chromatography, including clamping means, for engaging both end marginal portions of the plates which comprise a vertically disposed pair of movable locating members and a complementary pair of longitudinally extending resilient supporting members for the chromatography plates, said locating members and said supporting members being relatively movable to clamp the plates therebetween, the longitudinally extending sides of the apparatus including vertical sections which each form a plane abutment for a respective one of said locating members when lowered towards and raised from the resilient support, said vertical sections being spaced apart to snugly received between them the chrothe locating members are constituted as guide members for an applicator intended to slide between them in a coating operation, and ancillary means effecting a progressive relative movement between the pair of locating members and the pair of resilient supporting members to clamp the plates therebetween, comprising a plurality of similar cams coaxially mounted in equi-spacedrelation lengthwise in the apparatus, and means for simultaneously actuating the cams, rigid abutment means for the cams mounted transversely of the apparatus and connected to the clamping means, said abutment means coacting with said cams and being movably responsive thereto so that on the simultaneous actuation of the cams a progressive relative movement between the locating members and the resilient supporting members is obtained to clamp the chromatography plates in position for coating. 

